Efficiency Enhancement of Bredigite‐Structure Ca₁₄Mg₂[SiO₄]₈:Eu²⁺ Phosphor via Partial Nitridation for Solid‐State Lighting Applications

Abstract

We have synthesized a partially nitridated Ca13.7Eu0.3Mg2Si8O32 (CMSN:Eu2+) using Si3N4 with a conventional solid‐state reaction and successfully determined the structural parameters by a combined Rietveld refinement method. The partial nitridation of Ca13.7Eu0.3Mg2Si8O32 (CMS:Eu2+) led to a large enhancement in the luminescence intensity, as much as 148%. From the Rietveld refinement results, the anisotropic changes of the lattice parameters were observed for the partially nitridated samples. By incorporating this phosphor + red phosphor with an encapsulant on an InGaN light‐emitting diode (LED) (λmax = 395 nm), white light with a color rendering index of 92 and a color temperature of 5320 K under 20 mA was obtained.

Enhanced Luminescence of Ca14Mg2Si8O28+δN4−δ:Eu2+Phosphors by Codoping Ce3+, Mn2+ for White LEDs and Their Energy‐Transfer Mechanism

“…The emission of Eu 2+ in CMSN was at ~507 nm on exciting with 400 nm source as reported before . Codoping of Ce 3+ enhances the emission intensity of Eu 2+ greatly by transferring its excitation energy to Eu 2+ ions due to large spectral overlap between the emission of Ce 3+ and excitation of Eu 2+ ions.…”

Enhanced Optical Properties of Bredigite‐Structure Ca13.7Eu0.3Mg2[SiO4]8 Phosphor: Effective Eu Reduction by La Co‐Doping

“…(a). Previously, we reported that the thermal stability of CMS:Eu 2+ phosphors was not high . With the La and N incorporation into the host crystal, LaCMSN:Eu 2+ showed improved thermal stability compared with the CMS:Eu 2+ phosphors.…”

“…It was reported that defects sites such as oxygen vacancies are generated during the synthesis of the phosphors in high temperature . Because PL decay time is shortened by the increase in the nonradiative decay route, a shorter decay time of the LaCMSN:Eu 2+ with the increase in La and N contents means that the La and N introduction may induce defect sites, probably due to the charge imbalance by La 3+ /Ca 2+ and N 3− /O 2− .…”

Structural optimization for remote white light-emitting diodes with quantum dots and phosphor: packaging sequence matters

“…This type of pc-LEDs can achieve high LE, while their color rendering index (CRI) is rather poor due to the red spectral deficiency [4]. Many attempts have been made to improve the color rendering abilities of pc-LEDs, such as the addition of high efficiency red emissive phosphors [5][6][7][8]. However, they are incapable of maintaining high LE because their broad red emission partially lying outside the sensitive region of human eyes [8,9].…”